1. Field of the Invention
This invention relates to a probe module and, more particularly, to a digital logic module of oximeter sensor probe.
2. Description of Related Art
Generally, the conventional oximeter takes an external blood oxygenation signal to measure blood oxygenation level, by using a photodiode to detect an infrared and a red light trans-illuminated through the human body. Further, the oximeter will separate the infrared and the red light to perform amplifying for converting the analog signal to digital signal so as to perform operation to obtain the blood oxygenation level of a human body.
FIG. 1 illustrates a block diagram showing the conventional oximeter 10. The microprocessor 100 connects to the light emitting control circuit 110, the magnification amplifying control circuit 130, and the operation circuit 140, wherein the light emitting control circuit 110 connects to the light emitting unit 122 of the probe 120. The light emitting unit 122 comprises a red light source RED and an infrared light source IR, and the operation circuit 140 connects to the light sensitive element 121 of the probe 120. The light source driving program of the microprocessor 100 can generate a light source driving signal a1 to the light emitting control circuit 110 for controlling the red light source RED and the infrared light source IR of the light emitting unit 122. The microprocessor 100 can generate a light source pulse width modulation signal pwm to adjust brightness of the red light source RED and the infrared light source IR. The light source signal capturing program of the microprocessor 100 can generate a light source capturing signal a2 to the operation circuit 140. The operation circuit 140 controls the capturing cycle of the light source signal c1 of the light sensitive element 121 in the probe 120 based on the light source capturing signal a2. After emitting the red light source RED and the infrared light source IR to a finger of tester, the light source signal c1 is provided with blood oxygenation level. Further, the microprocessor 100 can control the magnification amplifying control circuit 130 to amplify the light source signal c1 of the operation circuit 140, and the operation circuit 140 can demodulate the light source signal c1 for being converted to a digital signal d1 through the A/D conversion. Finally, the microprocessor 100 will receive the digital signal d1 to perform operation for obtaining the value of the blood oxygenation level.
Although the implementation of such oximeters has been achieved, the light source driving program and the light source capturing program of the microprocessor 100 will occupy too much resource, resulting in causing inconvenience to the user and also increasing resource consumption during the operation period.